Inflation with vector interactions
Vector fields are usually assumed to decay away exponentially fast during inflation and therefore ignored. Nevertheless, with an appropriate coupling to the inflaton, vectors may play an interesting role. In this talk I will first give an introduction to inflation with the f^2F^2 interaction and review some of its rich phenomenology. Next I will focus on the role of super horizon vector fluctuations and their contribution to the primordial power spectrum. Contrary to the contribution from the background vector, their contribution is not deterministically determined by background parameters. Instead the huge cosmic variance associated with large scale fluctuations requires a stochastic approach and the prediction is in terms of a probability distribution function (PDF) which we estimate by Monte-Carlo simulations.